how to figure out cubic yds. in a coned shape pile of dirt.

[waste99]

I have several large piles of smashed concrete and soil combined, I need to figure out the formula to find cubic yards and tonnage. they are cone shaped, round at the base up to the point. I need to give a vendor a basic estimate.

[Dirtman]

I have several large piles of smashed concrete and soil combined, I need to figure out the formula to find cubic yards and tonnage. they are cone shaped, round at the base up to the point. I need to give a vendor a basic estimate.

The formula for the volume of a cone is: (PI*radius squared*height)/3

Using feet, the answer is in ft^3. Divide bt 27 to get yd^3. This will be an approximate value in loose cubic yards as compaction isn't known. If the stockpiles are recent it should be close but I would add 2% minimum to the total for compaction in place.

Tonnage can vary considerably depending on density of materials and moisture. Broken concrete will weigh comparably to broken limestone, about 95-100 pcf (pounds ft^3) and clay or pit-run sand and gravel can weigh over 110 pcf if wet.

If the stockpiled material is reasonably dry, 2835 per lcy (loose cubic yard) would probably be a decent approximation to use, which is 1.42 tons per lcy.

For your own calcs, here is a weights of materials chart: http://www.reade.com/Particle_Briefings/spec_gra2.html